Digital information may be transmitted via an air interface by modulating a high frequency carrier signal. The digital information may be created and processed at a symbol rate determined by the time which is reserved to transmit a single symbol over the air interface. When different symbols are transmitted, a smooth transition between subsequent symbols is created to avoid influencing neighboring channels and to maintain a desired quality of the transmitted signal. When the transmitted digital information is represented by symbols within the complex plane, trajectories in the complex plane are created between the consecutive symbols. The trajectories can thus be understood to be a representation of a complex valued signal generated by the transition between two subsequent symbols. The phase and the magnitude along the trajectories are modulated on the high frequency carrier to provide a smoothly varying modulated high frequency carrier. The modulation may be performed based on the magnitude or radius parameter R and the phase parameter φ or may be based on the real part (in phase component I) and the imaginary part (quadrature component Q) of the representation of the complex-valued signal defined by the trajectory in the imaginary plane.